Updated 4:26 pm, Friday, February 21, 2014

Tissue from a patient's liver shows minute bacterium, individually and in large clusters, stained red.

Tissue from a patient's liver shows minute bacterium, individually and in large clusters, stained red.

Photo: MD Anderson Cancer Center

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Late stage skin ulcers in a patient with diffuse lepromatous leprosy, a severe potentially lethal form of leprosy.

Late stage skin ulcers in a patient with diffuse lepromatous leprosy, a severe potentially lethal form of leprosy.

Photo: MD Anderson Cancer Center

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Large clusters of enriched and purified Mycobacterium lepromatosis upon 1000-fold magnification. Each organism is a few microns in length and is indistinguishable on morphology from other mycobacteria, such as Mycobacterium leprae, the other leprosy agent that is well known since initial discovery by Armauer Hansen in 1873.

Large clusters of enriched and purified Mycobacterium lepromatosis upon 1000-fold magnification. Each organism is a few microns in length and is indistinguishable on morphology from other mycobacteria, such as

SURABAYA, INDONESIA - JANUARY 29: Umar, 33, a former leper plays chess at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected disease, especially in the rural areas of the country where little is known about it and many suffer from the stigma and lack of knowledge surrounding the disease. Indonesia has around 25,000 leprosy sufferers, 30 % of them in East Java Province, giving it the third highest number of cases in the world behind India and Brazil. less

SURABAYA, INDONESIA - JANUARY 29: Formers leper takes out food from Babat Jerawat Leprosy Shelter officers on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected disease, especially in the rural areas of the country where little is known about it and many suffer from the stigma and lack of knowledge surrounding the disease. Indonesia has around 25,000 leprosy sufferers, 30 % of them in East Java Province, giving it the third highest number of cases in the world behind India and Brazil. less

SURABAYA, INDONESIA - JANUARY 29: Formers leper sits at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected disease, especially in the rural areas of the country where little is known about it and many suffer from the stigma and lack of knowledge surrounding the disease. Indonesia has around 25,000 leprosy sufferers, 30 % of them in East Java Province, giving it the third highest number of cases in the world behind India and Brazil. less

SURABAYA, INDONESIA - JANUARY 29: Imron, 41, a former leper wears a prosthetic leg at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected disease, especially in the rural areas of the country where little is known about it and many suffer from the stigma and lack of knowledge surrounding the disease. Indonesia has around 25,000 leprosy sufferers, 30 % of them in East Java Province, giving it the third highest number of cases in the world behind India and Brazil. less

SURABAYA, INDONESIA - JANUARY 29: Binti Nur Hidayah, 45, a former leper takes in her clothes at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected disease, especially in the rural areas of the country where little is known about it and many suffer from the stigma and lack of knowledge surrounding the disease. Indonesia has around 25,000 leprosy sufferers, 30 % of them in East Java Province, giving it the third highest number of cases in the world behind India and Brazil. less

SURABAYA, INDONESIA - JANUARY 29: Binti Nur Hidayah, 45, a former leper takes in her clothes at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected ... more

Photo: Robertus Pudyanto, Getty Images

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SURABAYA, INDONESIA - JANUARY 29: Binti Nur Hidayah, 45, a former leper takes in her clothes at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected disease, especially in the rural areas of the country where little is known about it and many suffer from the stigma and lack of knowledge surrounding the disease. Indonesia has around 25,000 leprosy sufferers, 30 % of them in East Java Province, giving it the third highest number of cases in the world behind India and Brazil. less

SURABAYA, INDONESIA - JANUARY 29: Binti Nur Hidayah, 45, a former leper takes in her clothes at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected ... more

Photo: Robertus Pudyanto, Getty Images

Image 11 of 13

SURABAYA, INDONESIA - JANUARY 29: Sutini, 49, a former leper wears a prosthetic legs at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected disease, especially in the rural areas of the country where little is known about it and many suffer from the stigma and lack of knowledge surrounding the disease. Indonesia has around 25,000 leprosy sufferers, 30 % of them in East Java Province, giving it the third highest number of cases in the world behind India and Brazil. less

SURABAYA, INDONESIA - JANUARY 29: Chalil, 34, a former leper sits on a pedicap with his braces at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected disease, especially in the rural areas of the country where little is known about it and many suffer from the stigma and lack of knowledge surrounding the disease. Indonesia has around 25,000 leprosy sufferers, 30 % of them in East Java Province, giving it the third highest number of cases in the world behind India and Brazil. less

SURABAYA, INDONESIA - JANUARY 29: Chalil, 34, a former leper sits on a pedicap with his braces at Babat Jerawat Leprosy Shelter on January 29, 2014 in Surabaya, Indonesia. Leprosy remains a largely neglected ... more

Dr. Han and his team found leprosy is five times more likely to be able to switch off the most significant antigens, eluding our immune systems to survive.

"What we need to ask now is how did it deactivate those antigens and why? And then we can say, those antigens might be helpful to us." said Dr. Han.

The new findings also reveal current leprosy bacterias date back 10 million years, making it the oldest known disease, with ancestors dating back up to 20 million.

It first lived freely in the atmosphere before taking on human hosts among our early ancestors. The only other species affected is armadillos, and it's thought they caught it from early American explorers.

Scientists say in concept we might be able to take this understanding to build new tools to help fight all diseases.

"The more we understand the origins of a disease, the more we understand the whole picture," said Dr. Han.